Add extra keywords for Hazard used in FbF

[lucernae]

FbF uses a forecast hazard, not actual hazard.

When analysis is made using forecast hazard for FbF, InaSAFE needs to know that it can potentially go into extra postprocess (for trigger thresholds, or priority intervention).
We need to embed keywords in the hazard to tell that this is a forecast based hazard trigger.

The extra keywords is needed for:

• Add new hazard classification
• Add keywords flag that tells that this is a forecast based hazard for FbF